DESCRIPTION (Adapted from the application's abstract): Several hundred thousand joint repairs or replacement procedures are performed in the United States each year involving post traumatic damaged articular cartilage. Due to the friction and stress, which act on the knee, current prosthetic materials used for cartilage replacement have limited durability and are not suitable for young patients. The major obstacle in using porcine articular cartilage for replacement is the immune response to alpha-gal epitopes (Gal alpha1-3 Gal beta1-NA-R) on the porcine cartilage matrix. The goal of this proposal is to diminish the immune response against porcine articular cartilage xenografts by enzymatic modulation of carbohydrate epitopes. Specific objectives are: to determine, in a cynomolgus monkey model, whether immune rejection of porcine cartilage is greatly diminished by elimination of alpha-gal epitopes with recombinant alpha-galactosidase to assess the extent of production of cartilage specific antibodies and antibodies to alpha-gal epitopes in the transplanted monkeys. The project may enable the development of cartilage xenografts as commercial product to be used for replacing cartilage in patients who would otherwise require knee placement. PROPOSED COMMERCIAL APPLICATION: Potential commercial application not available.